Sharks and their Relatives - Ecology and Conservation

Sharks and their relatives – the rays and chimaeras – are the diverse group of cartilaginous fishes (Class Chondrichthyes) that have evolved over 400 million years. Historically considered of low economic value to large-scale fisheries (and therefore neglected by fishery management agencies), today many of these fishes have become the target of directed commercial and recreational fisheries around the world, and are increasingly taken in the bycatch of fisheries targeting other species.
Unfortunately, most sharks and their relatives are characterised by K-selected life history traits, including slow growth, late sexual maturity, low fecundity and long life, resulting in low rates of population increase. Such life histories make these species highly vulnerable to overexploitation and slow to recover once their populations have been depleted.
Shark fisheries have expanded in size and number around the world since the mid-1980s, primarily in response to the rapidly increasing demand for shark fins, meat and cartilage. Despite the boom-and-bust nature of virtually all shark fisheries over the past century, most shark fisheries today still lack monitoring or management. For example, only a handful of the 125 countries that are now involved in shark fishing and international trade have even the most minimal management in place, and there is still no management for sharks fished on the high seas. As a result, many shark populations are now depleted and some are considered threatened.
Shark fishery management has been hampered by a lack of biological and fishery data. Growing international concern over the status of these species, however, has improved this situation in recent years. This report emphasises the widely acknowledged need to improve shark fishery monitoring, expand biological research and take management action. Yet while species-specific data are still needed, lack of information should not be used to justify the lack of management for these vulnerable animals. If any marine species demand precautionary management, as set out by the United Nations Food and Agriculture Organization (FAO) Precautionary Approach (1995), it is the sharks and their relatives, because of their well-documented vulnerability to overexploitation.
This report serves as an introduction to the ecology, status and conservation of the sharks and their relatives for a general audience. It draws attention to their unique biology and makes the case for expanded political and financial investment in research, monitoring and precautionary management for all fisheries taking sharks, skates, rays and chimaeras as part of their catch. Shark fisheries cannot be managed sustainably, nor shark populations remain viable, in the absence of new conservation and management initiatives.